Cross-linked Polysaccharide Filtration Aid for Bayer Process
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Solution Overview
Problem
The Bayer process for producing alumina trihydrate from bauxite ore faces inefficiencies in filtration steps, particularly in the separation of solids from liquids, leading to suboptimal filtration rates and residual moisture content in the filtered solid cake.
Innovation Solution
The introduction of cross-linked polysaccharides, such as cross-linked dextran or dihydroxypropyl cellulose, into the slurry before filtration enhances the filtration process by improving the separation efficiency and reducing the moisture content of the filtered solids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional filtration methods are used in the Bayer process, then the filtration process is simpler and requires fewer additives, but the filtration rate is lower and residual moisture in the solid cake is higher
Solution Approach 1:
A cross-linked polysaccharide composition is introduced as an intermediary substance to facilitate the filtration process. The composition acts as a mediator between the slurry and filter medium, improving filtration rate and reducing residual moisture without requiring fundamental changes to the filtration equipment or process design.
Solution Approach 2:
The invention changes the chemical composition parameters of the slurry by adding cross-linked polysaccharides. This modification alters the physical-chemical properties of the slurry, such as viscosity and particle surface characteristics, which in turn improves filtration performance and reduces residual moisture content.
2Quantity of substance
If conventional filtration methods are used, then the process requires fewer chemical additives, but the residual moisture content in the filtered solid cake is higher
Solution Approach 1:
The invention changes the chemical composition parameters of the slurry by adding cross-linked polysaccharides. This modification alters the physical-chemical properties of the slurry, such as viscosity and particle surface characteristics, which in turn improves filtration performance and reduces residual moisture content.
Solution Approach 2:
The invention uses composite materials - specifically cross-linked polysaccharide compositions that combine multiple functional groups and structures. These composite materials provide enhanced filtration aid properties, enabling more effective moisture removal from the solid cake while using relatively small quantities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of cross-linked polysaccharides significantly increases filtration rates and reduces the residual moisture in the solid cake, leading to more efficient solid-liquid separation and improved operational efficiency in Bayer process plants.
Implementation Method 1
The introduction of cross-linked polysaccharides, such as cross-linked dextran or dihydroxypropyl cellulose, into the slurry before filtration enhances the filtration process by improving the separation efficiency
Implementation Method 2
The use of cross-linked polysaccharides significantly increases filtration rates and reduces the residual moisture in the solid cake
Data Source
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AI summary
The invention provides methods and compositions for improving the production of alumina trihydrate. The invention involves adding one or more cross-linked polysaccharides to a filter used to separate solids from liquid in the Bayer process. The one or more polysaccharides can be a cross-linked polysaccharide (such as cross-linked dextran or cross-linked dihydroxypropyl cellulose). The cross-linked polysaccharides can impart a number of advantages including greater flow rate and lower residual moisture in the resulting cake.